I. Field
The following description relates generally to wireless communications systems, and more particularly to optimizing parameters that facilitate automated wireless handover performance between nodes.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as voice, data, and so forth. These systems may be multiple-access systems capable of supporting communication with multiple users by sharing the available system resources (e.g., bandwidth and transmit power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, 3GPP Long Term Evolution (LTE) systems including E-UTRA, and orthogonal frequency division multiple access (OFDMA) systems.
An orthogonal frequency division multiplex (OFDM) communication system effectively partitions the overall system bandwidth into multiple (NF) subcarriers, which may also be referred to as frequency sub-channels, tones, or frequency bins. For an OFDM system, the data to be transmitted (i.e., the information bits) is first encoded with a particular coding scheme to generate coded bits, and the coded bits are further grouped into multi-bit symbols that are then mapped to modulation symbols. Each modulation symbol corresponds to a point in a signal constellation defined by a particular modulation scheme (e.g., M-PSK or M-QAM) used for data transmission. At each time interval that may be dependent on the bandwidth of each frequency subcarrier, a modulation symbol may be transmitted on each of the NF frequency subcarrier. Thus, OFDM may be used to combat inter-symbol interference (ISI) caused by frequency selective fading, which is characterized by different amounts of attenuation across the system bandwidth.
Generally, a wireless multiple-access communication system can concurrently support communication for multiple wireless terminals that communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from the base stations to the terminals, and the reverse link (or uplink) refers to the communication link from the terminals to the base stations. This communication link may be established via a single-in-single-out, multiple-in-signal-out or a multiple-in-multiple-out (MIMO) system.
One aspect of wireless communications relates to the concept of handover that refers to the act of switching serving cells from one station to another during communications with user equipment such as a mobile device. For instance, handover can occur during mobility situations when a device leaves one service location and enters another. The ideal handover scenario is when service is handed over from one station to another without any loss or disruption to the current communications path. Unfortunately, various handover failures can occur with present systems. Such failures include radio link failures and call drops for example. Some of these failures relate to handover network parameters that are manually configured or improperly controlled. When these parameters are not optimally configured, handover failures can occur. The respective failures generally fall in to four main categories: Handovers that occur too early; handovers that occur too late; handovers that are not triggered properly; and handover that bounce back and forth between stations which is sometimes referred to as “ping-ponging.”